In this age, I use an open can (a long Wix filter cut in half with one end completely open) at the range when shooting my AR pistols, because it sends the sound and flash downrange, to the delight of my shooting friends at the range. Does not suppress the sound ... if you were in front of the gun, downrange. I keep them on my tools at home, to surprise uninvited visitors.
Ive heard of arrests and convictions for merely discussing the matter or manufacture. Not the best idea. I’m not trying to be a wise-guy... just putting it out there.